Flat panel displays, such as LCD and plasma television, have become increasingly popular and now almost dominate the market which used to belong to traditional CRT. Because flat panel displays are thin in profile, they are often mounted on walls, brackets, or other vertical flat surfaces in order to save space. For a better viewing angle, flat panel displays are often mounted on a support device which can be rotated to a desired angle. Numerous patents directed to mounting devices allow the viewing angle to be adjusted can be found.
U.S. Pat. No. 7,296,774 (Sung I. Oh) is directed to a viewing angle adjustment system, which provides a support arm to couple a monitor to a surface such as a wall or ceiling to remotely adjust the viewing angle of the monitor. The support arm includes at least one motor along a pivot axis in the support arm. The motor can be activated by a processor that receives the control signal provided by a remote control. The support arm may include a plurality of pivot axes with a motor mounted on each of the pivot axes to adjust the viewing angle with respect to the vertical and horizontal planes.
US 2007/0125917A1 (Sung Il Oh et al.) is directed to a motorized mount system for repositioning a monitor capable of extending a monitor from a reference plane, and tilting and swiveling the monitor in reference to X, Y, and Z axes. The motorized mount system includes a first pair of arms between a base plate and an adapter plate. The base plate is adapted to attach to a wall and the adapter plate is adapted to attach to a back side of the monitor. The first pair of arms includes two pivoting arms which are symmetrical with respect to each other. The proximal ends of the two pivoting arms are pivotally coupled to the base plate and the distal ends of the two pivoting arms are pivotally coupled to the adapter plate. At least one of the proximal ends of the first pair of arms can be engaged with a motor to rotate the distal end about its axis, which in turn extends or retracts the distal ends of the first pair of arms. Another motor can be coupled to the distal end of the first pair of arms to swivel the monitor side to side. Yet another motor can be coupled to the distal end of the first pair of arms to tilt the monitor up and down.
It is noted that the mechanisms shown in the above patents are generally in the form of links or arms. The links or arms have the advantage of structural simplicity, but are weak or too large when they are used to support an object having substantial weight, particularly if they are required to be rotatable. Furthermore, as the display panel gets larger and heavier, the structure of a support device formed of links or arms can be too weak to safely support it.
Furthermore, when the angle of a display is adjusted, the center of gravity of the device as disclosed above will be displaced away from the wall or the surface where the device/display is mounted, and the displacement will impose additional stress on the support device, especially in translational movement, further aggravating the problem of structural weakness of the support device.
U.S. Pat. No. 7,648,112 is directed to a flat panel display mounting device for securing a flat panel display to a support surface. The flat panel display mounting device comprises a plurality of members in the form of support panels pivotally connected together and a rotation control mechanism connected thereto so that the flat panel display mounted on the device can be rotated to a desired angle and the center of gravity of the flat panel display during rotation can be maintained as close to the support surface as possible, so as not to generate additional stress to the flat panel display mounting device. The inventors of the present invention, Jin Fang and Andrew H. Lew, are co-assignees of U.S. Pat. No. 7,648,112, which is incorporated herein by reference. The mechanism of the mounting device disclosed in U.S. Pat. No. 7,648,112 is applied to the present invention with some components added therein to electrically drive and control the mechanism.